Objective function based group-wise successive interference cancellation receiver for dual-rate DS-CDMA system

In this paper, objective function based group-wise successive interference cancellation (GSIC) receiver is proposed for a dual-rate DS-CDMA system. In the receiver, user signals are divided into 2 groups for their data rates. Initial bit estimates for the users in the group 1 are obtained by its matched filter (MF) bank. The initial bit estimates for the group 1 users are fed into the multi-user detection (MUD) algorithm that is based on iterative objective function optimization. The objective function is derived from the optimum multi-user detection. Then the estimates for received signals of the group 1 users are regenerated and summed up to be subtracted from the received signal. The initial bit estimates for the group 2 users are obtained by its MF bank using the received signal with multiple access interference from the group 1 users subtracted. The initial bit estimates for the group 2 users are also fed into the MUD algorithm that is based on iterative objective function optimization. These procedures are done in multiple stages to achieve desired performance. It is shown that the proposed receiver achieves significant performance improvement over the MF receiver, GSIC receiver, multi-stage PIC receiver, and multi-stage partial PIC receiver for a Rayleigh fading channel.